The UN is incapable of preventing aggressors like Vladimir Putin invading other countries, Ukraine’s Volodymyr Zelensky has claimed, as he made an impassioned call for reform of the General Assembly and Security Council to end Russia’s war on his country. The president came face-to-face with a Russian diplomat as he addressed the UN Security Council in New York for the first time since Moscow’s invasion of his country. Mr Zelensky urged reform of the world body, saying: “Humankind no longer pins its hopes on the UN when it comes to the defence of the sovereign border of nations.” He added: “We should not wait for the aggression to be over. We need to act now. Our aspiration for peace should drive the reform.” And accusing Moscow of “criminal and unprovoked aggression”, he called on the General Assembly to remove Russia’s veto power on the Security Council. The 15-member council has met dozens of times since Russia invaded Ukraine in February last year, but it has been unable to take any action because Moscow holds a veto. All eyes had been on a potential encounter between the Ukrainian president and the Russian foreign minister, but Mr Zelensky left the room before Sergei Lavrov spoke, avoiding any clash. Russian ambassador Vassily Nebenzia had objected to the Ukrainian leader’s addressing the gathering, but his protest was stifled by Albanian prime minister Edi Rama, president of the meeting. Mr Zelensky posted on social media afterwards: “574 days of pain, losses, and struggle have already passed since the start of the full-scale aggression launched by the state, which, for some reason, is still present here among the permanent UNSC members. In a long thread, he wrote: “All in the world see what makes the UN incapable. This seat in the Security Council, which Russia occupied illegally, through backstage manipulations following the collapse of the USSR, has been taken by liars whose job is to whitewash Russia’s ongoing aggression and genocide ... “Veto power in the hands of the aggressor is what has pushed the UN into a dead end… “It is impossible to stop the war because all efforts are vetoed by the aggressor.” His proposals include expanding membership of the security council to include Germany and the African Union, among others. He said the epicentre of efforts to protect territorial integrity and sovereignty and human rights, as well as preventing aggression and genocide should be with the UN’s General Assembly and Security Council. Ukrainian soldiers were doing what the UN should be: holding Russia back, he told the security council, he told members. “Ukraine exercises its right to self-defence,” Mr Zelensky said. “Helping Ukraine with weapons in this exercise, by imposing sanctions and exerting comprehensive pressure on the aggressor, as well as voting for relevant resolutions, would mean helping to defend the UN Charter.” The 193-member General Assembly has overwhelmingly voted several times to condemn the invasion and demand Moscow withdraw its troops. They say Russia has violated the 1945 UN Charter. Mr Lavrov accused Western states of using the charter on “a case-by-case basis exclusively based on their parochial geopolitical needs”, which had shaken global stability and fomented hotbeds of tension, he said. On Thursday, the Ukrainian leader is due in Washington to meet US president Joe Biden, members of Congress and military officials to urge continued support for its war effort. While a majority in Congress still support supplying military aid to Ukraine, sceptical voices among Republicans are growing louder as the war’s cost rises. Mr Biden plans to announce a new military aid package during Mr Zelensky’s visit. Read More Ukraine-Russia war – live: Zelensky accuses Putin of ‘criminal and unprovoked aggression’ violating UN charter Ukraine, Russia and the tense U.N. encounter that almost happened — but didn't Zelensky tells UN to not make deals with ‘evil’ Russia: ‘Ask Prigozhin whether Putin can be trusted’ Grain spat drags Ukraine's ties with ally Poland to lowest point since start of Russian invasion Ukraine rejects defective Leopard 1 tanks from Germany after finding ‘serious faults’ Ukraine's allies make legal arguments at top UN court in support of Kyiv's case against Russia